Voucher inventive therapies are an innovative and efficacious drug abuse treatment interventions that can promote treatment retention and sustained abstinence. However, these are relatively new procedures and little is known about the influence on efficacy of their component features or about how these features might be tailored for improved efficacy in specific populations. This project proposes to explore parameters of voucher incentive procedures that could improve their efficacy in the methadone treatment population. The emphasis is on improved incentives for shorter periods of abstinence from cocaine than have previously been possible, and that has produced encouraging results in a preliminary study. This brief abstinence procedures will be systematically evaluated for efficacy as a treatment intervention to initiate periods of abstinence from cocaine. The Brief Abstinence Test will also be used as an assessment to investigate more broadly parameters of financial-based incentive therapies. We will examine 1) influence of incentive reinforcement magnitude on abstinence initiation outcomes 2) risk and benefits of providing incentives within a complex voucher system versus a system that provides direct cash payments and 3) influence on abstinence success rates of targeting single (cocaine, opiates) versus multiple (both cocaine and opiates) illicit drugs. The project utilizes within-subjects study designs that can provide data on efficacy of critical treatment parameters in an efficient and cost-effective manner. The information to be obtained will further advance our understanding of incentive therapies and how these can be tailored for improved efficacy in specific populations.